Numerical Simulation of Crystallographic Corrosion:  Particle Production and Surface Roughness

We use a cellular automaton model to describe corrosion of a metal with crystalline defects. The line defects are distributed over the material mimicking screw or edge dislocations. The line-defect density and the corrosion probabilities of the metal surface site are the model parameters accounting for the crystallographic aspect of corrosion. The corrosion probability is higher for a site located on a line-defect than otherwise. Varying the model parameters, we investigate the roughness of the metal surface considering both its geometrical and chemical aspects. A complicated surface structure with a high geometrical roughness appears if the defect density is not too high. We show a strong correlation between what we call chemical roughness and the properties of the produced particles by the corrosion front. A mean field description is used to analyze the simulation results. For the long time, the simulation results show that the topography of the corrosion front changes from a defect-controlled regime to a situation where the stochastic aspect is the dominant factor.